Not Applicable
Not Applicable
Not Applicable
This invention relates to double pumps, which are driven by way of a common shaft, and in particular to double rotor vane pumps.
A double pump similar to this invention is known from U.S. Pat. No. 4,621,982 which utilized a rotary vane pump in conjunction with a radial piston pump. The double pump identified in U.S. Pat. No. 4,621,982 is only designed for failures of the radial piston pump and not for failures of the rotary vane pump. The double pump identified in U.S. Pat. No. 4,621,982 also relies on cam rings for operation, which add complexity and cost.
It is therefore an objective of this invention to overcome the disadvantages of the previous art through part reduction and simplification, and to provide a double rotor vane pump where either pump can fail while the remaining operating pump can maintain nominal pump performance.
Prior art has been insufficient in reliability to meet the needs of single engine aircraft, most of which employ a rotary vane pump to power critical attitude and navigation instruments. This invention used in said application will greatly increase safety of flight.
To obtain the desired result of reduced complexity and to expanded the failure modes to include either pump results in: a double rotor pump with both rotors being driven by shear means with designed in failure locations.
Each rotor of the double rotor vane pump is powered from a common drive shaft. Each rotor of the double rotor vane pump has the capability to fail its shearing device while having no effect on the other rotor of the pump.
Although many methods are possible, the simplest method envisioned by the inventor for allowing each rotor to fail independent of the other rotor is to incorporate a key area into the inner diameter of the rotor as a designed in shear failure point. Another method for allowing each rotor to fail independent of the other rotor is the use of shear pins at each rotor.
The double rotor vane pump design utilizes two rotors each housed in its own individual chamber. Each rotor/chamber is located along a common axis of rotation. Both chambers of the double rotor vane pump share a common intake. Reed valves or a shuttle valve are used to isolate a pump and protect it from contamination by residue from a failed pump.
The double rotor vane pump uses a drive shaft, which has a torsional shear load failure value, which is high enough to allow the shear means to fail at each rotor without failing the shaft. The double rotor vane pump""s drive shaft is also designed such that in the event of a drive shaft seizure, the drive shaft""s torsional shear load failure value will be low enough to not cause any damage to the double rotor vane pump""s drive source.